1. Technical Field
The present invention relates in general to downhole electrical submersible pumps (ESP) and, in particular, to an improved system, method, and apparatus for a stackable multi-stage diffuser with anti-rotation lugs for an ESP.
2. Description of the Related Art
Multi-stage diffuser pumps are typically assembled in a stack of diffuser components that are nested together. The diffuser stack slides inside a housing along an axis of the housing. The diffuser stack is subjected to compression by a bearing that is threaded into the housing until it makes contact with the top of the diffuser stack. The bearing is tightened to a calculated length, thus compressing the stack. This design prevents the diffusers from spinning inside the housing during operation due to the impellers that rotate inside them. The stack typically has grooves with O-rings that are located on the outer diameters (OD) of the diffusers to seal directly against the inner diameter (ID) of the housing itself. The O-rings are axially spaced apart in approximately one-foot increments throughout the axial length of the stack to contain any leakage between the diffuser faces and the housing. Although the O-rings are closely spaced apart, they are not used at every stage since the assembly and/or disassembly from the housing would become very difficult. In addition, the O-rings on the OD of the diffusers must slide across the internal threads of the housing when installing the stack into the housing, which can potentially cut and damage the O-rings. Thus, an improved diffuser stack design that overcomes these limitations would be desirable.